X-ray study of high-and-low luminosity modes and peculiar low-soft-and-hard activity in the transitional pulsar XSS J12270-4859
arXiv:2002.00978 · doi:10.1051/0004-6361/201936356
Abstract
XSS J12270-4859 (henceforth J12270) is the first low-mass X-ray binary to exhibit a transition, taking place at the end of 2012, from an X-ray active state to a radio pulsar state. The X-ray emission based on archival XMM-Newton observations is highly variable, showing rapid variations (10 s) from a high X-ray luminosity mode to a low mode and back. A flaring mode has also been observed. X-ray pulsations have been detected during the high mode only. In this work we present two possible interpretations for the rapid swings between the high and low modes. In the first scenario, this phenomenon can be explained by a rapid oscillation between a propeller state and a radio-ejection pulsar state, during which the pulsar wind prevents matter from falling onto the neutron star surface. In the second scenario, a radio pulsar is always active, the intra-binary shock is located just outside the light cylinder in the high mode, while it expands during the low mode. At variance with other transitional pulsars, J12270 shows two instances of the low mode: a low-soft and low-hard mode. Performing an X-ray spectral analysis, we show that the harder component, present in the low-hard spectra, is probably related to the tail of the flare emission. This supports the understanding that the flare mechanism is independent of the high-to-low mode transitions.
accepted for publication in A&A
References in corpus (12)
- A Radio Pulsar/X-ray Binary Link
- Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
- Unveiling the nature of INTEGRAL objects through optical spectroscopy. V. Identification and properties of 21 southern hard X-ray sources
- X-ray Variability and Evidence for Pulsations from the Unique Radio Pulsar/X-ray Binary Transition Object FIRST J102347.6+003841
- X-ray states of redback millisecond pulsars
- Identification of the High-Energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
- Searching for Outflows in Ultraluminous X-ray Sources Through High-Resolution X-ray Spectroscopy
- Discovery of Gamma-ray Pulsations from the Transitional Redback PSR J1227-4853
- Time-resolved optical observations of five cataclysmic variables detected by INTEGRAL
- Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4-650224
- RXTE determination of the intermediate polar status of XSS J00564+4548, IGR J17195-4100, and XSS J12270-4859
- Precise optical timing of PSR J1023+0038, the first millisecond pulsar detected with Aqueye+ in Asiago